Printer-slotter blank feeder



June 12, 1962 Filed Sept. 15, 1960 W. A. SCHULZ PRINTER-SLOTTER BLANK FEEDER 2 Sheets-Sheet l INVENTOR. 6%; 1-52 5cwu4z June 12, 1962 w, A. SCHULZ 3,038,720

PRINTER-SLOTTER BLANK FEEDER Filed Sept. 15, 1960 2 Sheets-Sheet 2 IN V EN TOR. ra Jae 6'- QSCHUL Z ted States. P316111;

3,038,720 PRINTER-SLOTTER BLANK FEEDER Walter A. Schulz, Baltimore, Md., assignor to Koppers Company, Inc., a corporation of Delaware Filed Sept. 15, 1960, Ser. No. 56,212 3 Claims. (Cl. 271-44) This invention relates to printer slotters and similar machines in which box blanks or the like made from stiff and relatively thick material such as corrugated paper are fed from the bottom of a stack of blanks resting on a table at the front of a machine by means of reciprocating feed members which engage the front edge of each blank in turn and advance it into the bite of the rollers. The stack of blanks is placed in front of the pull rollers by the gates and the feed members advance each bottom blank in turn from the gates into the bite of the rollers. As these require a definite period to pass each blank of a given width in the direction of feed to prevent overlapping of the blanks, it is necessary to coordinate the rate of feed of the reciprocating member with the speed of the rollers so as to prevent overlapping within the rollers.

In order to accommodate the machine to handle blanks of widely diiferent widths, provision is made to feed successive blanks at spaced intervals so that the blanks narrower than a given median width dimension are fed at relatively short intervals and those wider than this dimension are fed at longer intervals. This is accomplished by only feeding the blanks to the rollers upon alternate or every other stroke of the reciprocating speed mechanism. This prevents the overlapping of the blanks within the pull rollers and in this manner the time interval between the feeding of blanks of different widths is efficiently accomplished. This type of alternating feed of the blanks is generally designated as a skip feed mechanism.

To achieve the alternate feeding, conventionally the front edges of the blanks are raised above the feed mechanism once for every two strokes of the latter so that it is ineffective to engage the front edge of the blank during its forward or feeding structure when the stack is elevated.

It is an object of the present invention to provide an improved skip feed mechanism.

It is a further object to provide a skip feed mechanism constructed and arranged so that the accommodation of the feed mechanism to definite widths may be more easily accomplished than heretofore.

It is still another object of the invention to provide a new and novel stack lifting mechanism.

It is still a further object to provide an electro-pneumatic control for actuating the stack lifting mechanism.

In essence, the invention as embodied in a printer slotter having a feed table adapted to support a stack of blanks of stiff material and having a reciprocating feed including means for engaging the front edge of each blank in turn comprises means for supporting the front edges of said plurality of blanks above the feed table, means upon which the supporting means are rotatably or pivotally mounted for moving the blanks into and out of the path of the feeding mechanism and electro-pneumatic control energized by said reciprocating means for alternately turning said supporting means into and out of the path of the feed so that sheets of blanks of material are alternately fed across said feed table.

In the accompanying drawings,

FIG. 1 is a plan view of a feed table used in a printer slotter feed mechanism and embodying the present invention.

FIG. 2 is a view taken substantially along the lines 2-2 of FIG. 1 showing the arrangement of the limit switch employed in the electro-pneumatic system in the present invention.

Fllglq. 3 is a side view of the feed table illustrated in FIG. 4 is a view taken substantially along the lines 4-4 of FIG. 1 showing a detail of one of the lifting elements of the lifting mechanism.

FIG. 5 is a schematic view of the electro-pneumatic controls.

Referring now to the drawings, there is shown a feed table 1 which is suitably supported on the printer slotter side frames 2 and 3 on Which there is carried the usual feed gate and pull rollers (not shown). Mounted adjacent the rear of the feed table 1 is a stack supporting mechanism 4 for holding the front edge of the stack of blanks above the table surface comprising two supporting blocks 5 on which there is fastened a channel 6. The blocks 5 and channel 6 are fixed as by adjustable clamp 8 to guide rails 9 and mounted in slots 10 extending longitudinally of the bed so as to permit sliding movement relative to the feed gate and thereby accommodate blanks of different widths. The clamp and guide means is of more or less conventional structure.

Spaced along the channel 6 and fastened thereto are pairs of supporting trunnions 11 supporting a shaft 12 for rotation relative thereto. Fixed to the shaft 12 for turning therewith are a plurality of lifting brackets 13 each of which is supported between one of the pair of trunnions 11. Secured to the bottom of each of the lifting brackets 13 and extending forwardly is a lip 13a forming a ledge which supports the front edge of the stack of blanks B above the feed table.

Fixed to the end of the shaft 12 projecting outwardly of the tab-1e 1 and supported between trunnions 11 is an actuating lifting bracket 14 provided with the forwardly extending lip 13a and having a rearwardly extending arm 15 formed with a yoke 16. Turnably supported within the yoke 16 by a stud 17 is an eye bolt 13 into which there is threaded the end of a plunger 19 of an air cylinder 20.

Encircling the body of the air cylinder 20 is band 21 carrying diametrically opposed rotatable pins 22 on which there is fastened as by a force fit one end of supporting arms 23. The other end of the arms is adapted to rest on plates 24 secured to the transverse channel 6. The supporting structure of the air cylinder 20 above described permits a limited turning thereof as the plunger 12 advances and retracts. cylinder 20 is attached to channel 6 for movement with the latter. The air cylinder 20 is an element of the electro-pneumatic control system hereinafter to be described in greater detail.

.Forwardly of the stack lifting mechanism is the reciprocating feed slide 25. The feed slide 25 is suitably fastened to sliding feed bars 26 supported in grooves 17 extending longitudinally of the feed bed 1. Connected to one end of the feed bars 26 for moving the slide to and from the forward edge of the feed table are cranks 50 connected to a rocker shaft 51 which are actuated in the conventional manner. The feed slide 25 is provided with the usual feeding elements 25a.

As shown in FIG. 3, the rear end 26a of feed bar 26 on its return stroke extends beyond the stack lifting mechanism 4. Fastencd to the underside end 26a of one of the bars 26 is a cam 40 which engages a switch arm 27a of a limit switch 27 of the skip feed control system S.

The skip feed control system S comprises generally the air cylinder 20 connected by way of flexible lines 28 and 29 to a four-way solenoid valve 30 which is connected to a suitable air pressure supply 31. The four-way solenoid valve 30 is electrically energized by way of limit switch 27. The limit switch 27 is of the type having adjustment means for selectively opening and closing the contacts 36 thereof and thereby energize the solenoid valve 30 and actuate the It is also to be noted that the air plunger 19 of the air cylinder 20. present invention wherein it is desired to energize the lifting mechanism only upon alternate strokes of the feed slide, the adjusting mechanism of the limit switch is positioned so as to only close and energize the pneumatic controls upon alternate strokes when the cam 40 engages the limit switch arm 270. Also connected in the electrical circuit is a manually operated switch 27b which may be conveniently mounted on the printer slotter frame for easy access by the operator so that manual adjustment may be made.

In operation, the stack supporting mechanism is positioned on the feed bed 1 to accommodate the width of the blank by way of the conventional adjustment clamps 8 and guide rails 9. As pointed out before, the air cylinder supported on channel 6 for raising and lowering the lifting brackets is concurrently moved. Thereafter the feed slide 25 is set into operation to reciprocate and when the feed bar 26 returns to its retracted position, the cam 49 engages the arm 27a of limit switch 27. The limit switch 27 is set to energize the circuit of the solenoid valve 30 upon alternate return strokes of the feed bar 26. When the switch 27 is closed on the alternate stroke, the solenoid valve 30 is energized whereupon the plunger 19 of the air cylinder 20 is retracted. The retraction of the plunger 19 secured to the lifting arm 15 of the actuating lifting bracket 14 turns the latter clockwise as viewed in FIG. 3 and thereby turns the shaft 12 and accordingly also turns the lifting brackets 13 a corresponding amount. Accordingly, the stack of blanks B supported on the ledge 13a of the lifting brackets 13 are elevated above the slide feed bar so that when the latter moves forwardly into its feed stroke, it does not engage the front edge of the lower blank so that no blanks are fed. On the other stroke, when the limit switch 27 is inoperative to energize the valve 30 and air cylinder 20 as described above, the plunger 19 remains in its extended position so that when the feed slide bar 25 moves forwardly, it engages the front edge of the lower blank so as to feed it into engagement with the gate and pull rollers whereupon the latter is operative to move the blank into the printer slotter for further operation thereon.

What is claimed is:

1. In a printer slotter having a feed table adapted to support a stack of blanks of stiff material and a reciprocating feed device including feeding elements for engaging the front edge of each blank to advance each blank in turn from beneath the stack projections for supporting the front edges of the stack of blanks above the top of the feed table, the improvement comprising a rotatably-mounted shaft to In accordance with the V strokes of said reciprocating feed device during which the stack of blanks is in the feeding position.

2. In a printer slotter having a feed table adapted to support a stack of blanks of stiff material and a reciprocating feed device, the combination including means for engaging the front edge of each blank to advance each blank in turn from beneath the stack, means for supporting the front edges of the stack of blanks above the top of the feed table, said supporting means comprising a rotatable shaft, means fixed to said shaft for rotating therewith including projecting ledges on which the front edge of said blanks rest and electro-pneumatic means connected to said shaft and actuated by said reciprocating feed device for rotating said shaft on alternate strokes of said reciprocating feed device to move the stack of blanks into and out of engagement with said engaging means whereby a blank of material is fed across the feed table on alternate strokes of said reciprocating feed device.

3. In a printer slotter having a feed table adapted to support a stack of blanks of stiff material and a reciprocating feed device, the combination including means for engaging the front edge of each blank to advance each blank in turn from beneath the stack, means for supporting the front edges of the stack of blanks above the top of the feed table, said supporting means comprising a rotatable shaft, means fixed to said shaft for rotating therewith including projecting ledges on which the front edge of said blanks rest, electro-pneumatic means connected to said shaft for rotating the latter, and limit switch means operative on alternate strokes of said reciprocating feed device to actuate said electro-pneumatic means and thereby rotate said shaft so that a single blank of material is fed across the feed table on alternate strokes of said reciprocating feed device.

References Cited in the file of this patent UNITED STATES PATENTS 2,226,588 Simpson Dec. 31, 1940 2,289,010 Greenwood July 7, 1942 2,632,644 Wockenfuss et al Mar. 24, 1953 

